A Substudy of Investigational Agents in Programmed Cell Death-1/Ligand 1 (PD-1/L1) Refractory Locally Advanced or Metastatic Urothelial Carcinoma (mUC) (MK-3475-04A)

Open to people ages 18 years and up

The main inclusion and exclusion criteria include but are not limited to the following:

• Histologically or cytologically confirmed diagnosis of locally advanced/unresectable or mUC of the renal pelvis, ureter (upper urinary tract), bladder, or urethra.
• PD-1/L1 refractory locally advanced or mUC as evidenced by:

EITHER disease progression while on treatment or after treatment with an anti-PD-1/L1 monoclonal antibody (mAb) for locally advanced/unresectable or mUC administered either as monotherapy, or in combination with other checkpoint inhibitors or other therapies OR disease recurrence while on treatment or after treatment with an anti-PD-1/L1 mAb for muscle-invasive urothelial carcinoma (MIUC) administered as monotherapy.

• Participants must provide an archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion demonstrating UC, not previously irradiated, and adequate for biomarker evaluation.

• Known additional nonurothelial malignancy that is progressing or has required active treatment within 3 years prior to study randomization/allocation.
• Received prior systemic anticancer therapy including investigational agents within 4 weeks before randomization/allocation.
• Active infection requiring systemic therapy.
• Received a live or live-attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed.
• Known history of human immunodeficiency virus (HIV).
• Known history of hepatitis B or known hepatitis C virus infection.